A 21-Year-Old Man

and Iain McNamara¹

(1)

Trauma & Orthopaedics, Norfolk & Norwich University Hospital, Norwich, United Kingdom

A 21-year-old man presented to the clinic with long-standing problems with both knees. From the age of 7 years old, he had had pain and stiffness in his knees. He gave up soccer at the age of 12 years and martial arts at the age of 14 years; the latter following a number of falls directly onto his knee. At the age of 14, he dislocated his left patella. His left knee was never been normal after that. His right knee had been a problem over the previous 2 years with recurrent patellar dislocations.

On Examination

He had no internal rotation of his hips and 90^° of external rotation. He had a non-correctable valgus with an intermalleolar distance of 4 cm. He had an external torsion of his tibiae clinically at about 20^°. Both patellae tracked straight. There was no patellar apprehension and the mediolateral glide was ++. On the right he had an uncomfortable click during flexion. His trochleae were flat on palpation.

Question 1

What do you expect the plain radiograph images to show and why?

Question 2

How would you classify the trochlear groove?

Question 3

What further imaging should you obtain?

Following his imaging the CT scan was reported as:

Femoral Rotational Angles

Right: 17° internal rotation of the femoral condyles with respect to the femoral neck
Left: 2° internal rotation of the femoral condyles with respect to the femoral neck

Tibial Rotational Angles

Right: 17° external rotation of the distal tibial plafond with respect to the femoral condyles
Left: 21° external rotation of the distal tibial plafond with respect to the femoral condyles

Question 4

What does the axial CT scan show?

Question 5

What procedures would you plan to do for an operative correction?

Operation Left Knee

When seen in the pre-admission clinic, he was found to be very anxious. When examined under anaesthetic, the patella was found to be subluxatable, but not dislocatable laterally. The mediolateral glide was ++++. The trochlear boss was easily palpable.

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